Plan R3S1 



24. Plan R3S1 (Plate 5, and Photos 9 and 10) was similar to the pre- 

 ceding plans except the weight of the primary armor stone (Wp) was increased 

 to 4.9 tons. The greater stone size resulted in an increase of the crown 

 elevation to 4.8 ft msl. 



25. When subjected to the abbreviated storm-surge hydrograph, Plan R3S1 

 demonstrated improved stability as compared to the previous plans. However, 

 as shown in Photos 11 and 12, the design was unacceptable due to excessive 

 movement of the primary armor stone. 



Plan R4S1 



26. Plan R4S1 (Plate 6, and Photos 13 and 14) was constructed using 

 6.3-ton primary armor stone (W2) placed on a 1V:3.5H slope. The crown 

 elevation was increased to 5.0 ft msl and the elevation of the stapods was 

 increased by placing them on the underlayer stone (Wj^). 



27. When subjected to the abbreviated storm-surge hydrograph, damage to 

 Plan R4S1 was minor and the stability response was considered acceptable. 

 Some armor stones shifted positions as they sought a more stable orientation 

 and one 6.3-ton stone was carried seaward of the stapods. As waves struck the 

 vertical seawall, energy directed downward had a tendency to force stone lying 

 adjacent to the wall slightly seaward. Eventually some settlement occurred; 

 however, the overall integrity of the section was not affected, and it was 

 decided to subject this design to the full-scale storm-surge hydrograph. 

 Photos 15 and 16 show the condition of the structure after testing with the 

 abbreviated hydrograph. 



28. Exposure to the 13-hr storm-surge hydrograph was initiated. Re- 

 sults obtained were very similar to those observed with the abbreviated 

 hydrograph. There was some minor damage due to stone displacement during the 

 earlier hydrograph steps and again one of the primary armor stones was carried 

 seaward to the toe area. The most severe problem resulted in a significant 

 damage in the area adjacent to the seawall. Because of severe wave impact at 

 the wall, forces directed down the face of the cutoff wall were able to grad- 

 ually cause scour, settlement, and a seaward displacement of material at the 

 seawall-revetment interface. This damage did not involve the displacement of 

 individual armor stones; instead, the entire revetment section was moved 

 slightly seaward as a unit. Photos 17 and 18 show the settlement at the wall, 

 the wedge-shaped gap between the cutoff wall and the revetment, and the 



17 



